This invention relates to decorative panels for appliances. More particularly, the invention relates to the use of laminated structures for providing these decorative panels.
An appliance generally has a visible external surface. Such a surface can consist of a decorative panel that can be painted or constructed of colored material for aesthetic purposes. For instance, a dishwasher, trash compactor, or other kitchen appliance can have a decorative front surface. A front panel of an appliance can be interchangeable so that a user can change the decorative look of the appliance. For example, multiple panels of different colors can be provided with the appliance, so that a user can select and install a desired panel.
In other types of appliances, for example clothes washers and dryers, stoves and refrigerators, panels may be shaped to form corners, such that areas other than just the front of the appliance may be covered. In any of these ore other applications, it is sometimes desirable to use a panel providing special visual effects. One particularly desirable effect, especially for consumer-oriented appliances, is a high Distinctness of Image (DOI).
Distinctness of image is defined as the sharpness with which object outlines are reflected by a surface. This measurement is frequently used by automotive and architectural coatings manufacturers to indicate the quality of a finish, with high DOI levels (up to a maximum possible value of 100) being desired. Additionally, it is desired that surfaces have the same, or at least nearly the same, DOI when viewed from different angles. Thus it is common to measure DOI of a surface from two different, mutually perpendicular directions.
In the typical situation, the object of interest is some kind of sheet material that has been manufactured on a line, and which therefore has an identifiable machine direction (MD) and a transverse direction (TD) perpendicular to it. Frequently, DOI in the machine direction is higher than that in the transverse direction, typically by a large margin. The relative equality of these measurements is commonly captured as a ratio of MD to TD, with a value of 1.0 being ideal. Ratios of MD to TD vary widely, depending on the type of surface and the type of process utilized to apply a glossy finish to the sheet, and in many cases may be about 1.5 or even higher. Such high DOI ratios are however undesirable for products in certain market niches.
Many different types of surface finishes exist, and accordingly, DOI measurements vary widely accordingly. Water-based coatings, desirable from an environmental perspective, tend to give poor DOI in both the machine direction and the transverse direction. Solvent-based coatings tend to give better DOI, but require solvent control measures and disposal procedures in order to meet environmental needs. In addition, solvent based coatings applied by a roller coating process tend to have a DOI in the TD significantly lower than in the MD, resulting in an inferior quality finish. Additionally, finishes based on coating with a water-based or solvent-based composition typically suffer from imperfections due to roughness and unevenness in the coating as applied, or due to roughness and/or imperfections in the surface receiving the finish.
In International Publication Number WO 97/11847, issued as EP 0 862 514 B1. Donnelan et al disclose a composite polyester sheet having an opaque polyester core layer, a transparent polyester outer layer on a first surface of the core layer, and a heat-sealable layer on a second surface of the core layer. The composite sheet is said to be suitable for laminating to a metal sheet for the production of cans, and is said to reduce or substantially overcome problems relating to excessive wear of punches/dies used for forming the can, and/or scoring of the can surface. The core layer and/or transparent outer layer are preferably biaxially oriented to achieve a satisfactory combination of mechanical and physical properties, but they may be uniaxially oriented. There is no mention of optical properties such as DOI in this patent application.
There continues to be a need for providing sheet metal based panels for appliances, exhibiting high distinctness of image and a ratio of distinctness of image in the machine direction vs. the transverse direction of close to 1 for manufacturing consumer products, particularly decorative panels for appliances.
In one aspect, the invention is an appliance panel comprising a laminated structure. The structure comprises a substrate sheet having adhered thereto a biaxially oriented film composite comprising a colored polyester layer adjacent and coextensive with a clear layer comprising a polyester. The colored polyester layer lies between the substrate sheet and the clear layer, and the laminated structure has a machine direction and a transverse direction corresponding to that of the film composite. The laminated structure forms a viewable surface of the appliance panel; and the laminated structure has a machine direction distinctness of image greater than about 80, a transverse direction distinctness of image greater than about 80, and a ratio of the machine direction to the transverse direction distinctness of image of less than 1.30.
In another aspect, the invention is an appliance comprising a panel, the panel comprising a laminated structure. The structure comprises a substrate sheet having adhered thereto a biaxially oriented film composite comprising a colored polyester layer adjacent and coextensive with a clear layer comprising a polyester. The colored polyester layer lies between the substrate sheet and the clear layer, and the laminated structure has a machine direction and a transverse direction corresponding to that of the film composite. The laminated structure forms a viewable surface of the appliance panel; and the laminated structure has a machine direction distinctness of image greater than about 80, a transverse direction distinctness of image greater than about 80, and a ratio of the machine direction to the transverse direction distinctness of image of less than 1.30.
In yet another aspect, the invention is a method of making an appliance. The method comprises providing a laminated structure. The structure comprises a substrate sheet having adhered thereto a biaxially oriented film composite comprising a colored polyester layer adjacent and coextensive with a clear layer comprising a polyester. The colored polyester layer lies between the substrate sheet and the clear layer, and the laminated structure has a machine direction and a transverse direction corresponding to that of the film composite. The laminated structure forms a viewable surface of the appliance panel; and the laminated structure has a machine direction distinctness of image greater than about 80, a transverse direction distinctness of image greater than about 80, and a ratio of the machine direction to the transverse direction distinctness of image of less than 1.30. The method also comprises forming the laminated structure to provide a viewable surface of the appliance.
In a further aspect, the invention is a motor vehicle panel comprising a laminated structure. The structure comprises a substrate sheet having adhered thereto a biaxially oriented film composite comprising a colored polyester layer adjacent and coextensive with a clear layer comprising a polyester. The colored polyester layer lies between the substrate sheet and the clear layer, and the laminated structure has a machine direction and a transverse direction corresponding to that of the film composite. The laminated structure forms a viewable surface of the motor vehicle panel; and the laminated structure has a machine direction distinctness of image greater than about 80, a transverse direction distinctness of image greater than about 80, and a ratio of the machine direction to the transverse direction distinctness of image of less than 1.30.